A gas turbine engine typically includes a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section.
In gas turbine engines, mechanical seal assemblies are used to prevent hot, high pressure air from entering a bearing compartment that operates at a low pressure and temperature. For example, a front bearing compartment in a multiple spool gas turbine engine is filled with an oil mist to lubricate the bearings that support the high speed rotor shaft and the low speed rotor shaft. The high speed rotor shaft and the low speed rotor shaft are separated by a gap filled with working medium gas. The working medium gas cools the rotor shaft. An intershaft seal assembly is required to keep leakage between the two regions within acceptable amounts during operation.
Speed variations between shafts experienced by each face seal can result in uneven loading. Moreover, limited space is available within bearing compartments at the interface between shafts sealing between the high and low speed rotor shafts.
Accordingly, it is desirable to provide a dual configuration intershaft seal assembly for a rotational assembly having rotor shafts including different sealing requirements that reduces seal assembly design space, reduces cost and reduces the overall weight of the assembly.